Abstract: Alkenyl ether-siloxane compositions comprising(A) an oligomeric or polymeric organosilicon compound having on average more than one alkenyloxy group of the formulaR.sup.2 --CH.dbd.CH--O-- (VI)(B) a monomeric maleic and/or fumaric acid compound of the formula ##STR1## in which R.sup.2 is a hydrogen atom or the methyl radical,R.sup.3 is identical or different and is a hydrogen atom, a hydrocarbon radical having 1 to 16 carbon atoms, which can be interrupted by oxygen, sulfur or oxygen- or silicon-containing units, a substituted hydrocarbon radical having 1 to 6 carbon atoms, a silyl radical or a siloxanyl radical,R.sup.4 is identical or different and is a hydrogen atom, chlorine, bromine, fluorine or an optionally substituted alkyl radical andZ is an oxygen atom or a radical --NR.sup.5 --, where R.sup.5 has one of the meanings given for R.sup.3,optionally(C) initiators which form free radicals and optionally(D) inhibitors for regulating the pot life.